Seems like what is going on for fishing the South Fork applies to the lower Henry’s Fork. Afternoon BWO activity, caddis later in the afternoon, and mostly presenting streamers to migrating browns. BWO activity rules the roost at the Last Chance-Harriman stretch, while streamer fishing in Box Canyon and The Tubs is the order of the day. If you plan on fishing the upper river, watch the weather.
Notice that what happens on the lower Henry’s Fork (Warm River to St. Anthony) is similar to what is going on this time of year on the South Fork. On both rivers flow is dropping to base level. BWOs, mahogany duns, and midges provide the best dry fly fishing. Streamer presentation gains in effectiveness as the fall season advances through November as brown trout make spawning runs. If switching to streamers is to your liking, the best places on the upper river this time of year include Box Canyon, the base and the top of Coffee Pot Rapids, and The Tubs above Mack’s Inn.
If you enjoy streamer fishing, now begins the time that Box Canyon is great, especially during a stormy day like today. Another such location is “The Tubs” where Henry’s Lake Outlet and Big Springs Outlet combine above Mack’s Inn. This time of year fish move downstream from the river in the Flat Ranch to the deep cover in these holes. There are several other locations along the river where streamers are very effective now. From Warm River to Ashton is particularly good. So is the river just below Ashton Dam. Want to pitch streamer patterns in a tranquil location free of boats? Try the river at Bear Gulch, just above Mesa Falls Park, and below Coffee Pot Rapids as well as “The Tubs.”
If you enjoy the BWO emergence anywhere along the river, do not overlook using soft hackle patterns (partridge and olive , size 14) for emerger imitations.
The lower river offers a variety in dry fly fishing, and the turn in the weather predicted for next week can only help with respect to active fish. Along the lower river terrestrial insects still inhabit banks in good numbers. BWO and mahogany duns numbers will increase with the change in weather. The evening caddis emergence continues. Streamer fishing is improving, and get even better with unsettled weather. Tricos, a few remaining PMDs, and increasing BWOs make for good fishing in the Last Chance-Harriman section. Box Canyon offers good nymphing, with streamer fishing sure to pick up. The river in the Flat Ranch is pretty much done for the season.
Streamer fishing on lower river is picking up as browns begin spawning migrations. Choose low light conditions for best chances of encountering one, and have both somber and bright patterns in that fly box. BWOs and mahoganies are also emerging, so mid-day dry fly fishing can be good. Consider that wind will blow concentrations of these mayflies to the down-wind side of the river, so position yourself accordingly when presenting dun patterns.
Not much change here with AM trico swarms, daytime terrestrial insect activity, and evening caddis activity. This applies to just about the entire river. As browns begin to migrate in the lower river streamer fishing will be increasingly effective, especially during low light conditions. The lower river is cooling so look for tiny BWOs to become active enough to interest trout.
Terrestrial insect season is going on up and down the river. Exceptions include AM trico mating-spinner falls and evening caddis activity. PMD activity is greatly diminished and speckled duns are important only on slow river reaches such as the Flat Ranch and Harriman State Park. When cloudy days arrive streamer fishing will be more effective during mid-day rather than just around first light and twilight. Tiny BWO activity on the lower river is several days away.
As with our small streams report, anywhere you try the Henry’s Fork be sure to have grasshopper patterns in that fly box these days. Other events attract trout including evening caddis hatches on most of the river, spinner falls, and speckled dun emergences on the slower portions of the river. But nothing is as totally attractive to trout this time of year as hoppers. Look out for recreational floaters going through Box Canyon, especially during weekends. Anyone seen any honey ants other than around the Harriman section?
Anywhere on the river cloudy skies and high relative humidity will improve your mid-day fishing success. Patterns for spinner falls, caddis (life cycle patterns during evening hours) streamers, and terrestrial insects can be most effective during these times of day and under these atmospheric conditions. On the upper river the arrival of honey ants will boost trout’s desire to come to the surface any time.